


There's No Time To Explain, Let's Fight Monsters

by Dolphinsrulecarly



Category: Arrow (TV 2012), Supernatural
Genre: Angst, Crossover, F/M, M/M, not too much tho, this is me thinking out loud tbh
Language: English
Status: In-Progress
Published: 2018-06-30
Updated: 2018-07-07
Packaged: 2019-05-31 06:49:31
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,355
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15114047
Author URL: https://archiveofourown.org/users/Dolphinsrulecarly/pseuds/Dolphinsrulecarly
Summary: This occurs a few days after Dean tells Cas to leave the bunker. Somewhere in Arrow that I have no idea about. This is written entirely from a Supernatural fan's perspective, I don't hardly even watch Arrow.When Cas shows up cold, wet, and human on the Arrowcave's doorstep Felicity is forced to reveal her past and the Supernatural world to her team. Through the power of just talking shit out she manages to get Gadreel (The Angel possessing Sam) to join Team Free Will. Though, while her friends are visiting her and picking up Cas in Starling City, there's a massive explosion that kills everyone in a diner. Team Free Will automatically recognize it as an Angel attack. Are they there for Cas or Gadreel? Or for something far worse? They're going to need Team Arrow's help if they hope to take down the Faction of Angels setting up in Starling City.





	1. Ch1 Shut Up While I Fix This

**Author's Note:**

> Enter Human!Cas, who somehow knows Felicity? Team Arrow's confused but it doesn't look like they're getting answers this chapter, but Dean does explain things to Felicity while Cas takes a shower. Can they fix this?

Felicity was typing away at her computer, Oliver and Thea were currently sparring on the mats while Digg patched himself up from when he’d opened up his stitches, again, when a tentative knock at the Foundry’s door was heard, which was supposed to be a wall in the back of Oliver’s club. Suspicious.

The other three were suddenly armed with weapons and heading up the stairs, Felicity already had eyes on the person outside with her birds eye view from their many security cameras.

She didn't recognize him at first, after all he was wearing jeans and a hoodie, his face unshaven. He stood differently now as well, far less confident and more… human.

In fact she didn't recognize him until Oliver had the door open, him inside, and two arrows aimed at his heart and a gun at his head.

“F-Felicity, I came to ask a huge favor, but I realize now it was not smart to come here after your apartment was empty.” Felicity’s eyes blew out of her head.

“Cas?!” He looked at her, fear in his eyes.

“I-I’m human now and can be killed by any of the weapons aimed at me, p-please point them away.”

“Guys let him go!” She rushed forward.

“Cas! Wait here.” She ordered suddenly, and she came back with a duffel bag the others of her team had never seen. She handed the stranger a silver flask. He looked at her in understanding, taking it from her and made a show of drinking from it. She suddenly brought a spritz bottle of cleaning solution and spritzed it on his hand as he handed the flask back. She hurriedly stuffed them back into her pack.

“Cas!” She lunged forward and hugged him. He almost stumbled back and fell, but he caught himself on a table.

The rest of her team stood awkwardly to the side. Who was this guy? Why did she give him that flask, and spritz his hand?

“Are you okay? What are you wearing? Where's Sam and Dean? Why are you here? There isn't a case I missed is there? Why haven't any of you contacted me in like, a month!? How's the whole Gates of He-” She realized they had an audience and stopped.

“Uh, first…” Then she turned to her team.

“Guys, this is my pseudo brothers’ friend, Castiel, also known as part of my family.” He gave her an uncharacteristically warm smile.

“Cas, this is my team, Team Arrow. Oliver, Dig, and Thea, Oliver’s sister.”

“It’s nice to meet you. I'm sorry for interrupting earlier, but Felicity was not in her home, as far as I knew, and I desperately needed somewhere warm to stay for the night, I’m unsure if my body could have survived another freezing night outside without food.” Felicity looked grief stricken by this statement.

“Cas, what happened over the last month? Where’s Sam and Dean,” her voice lost the soft tone and became panic, “why aren't you with them? What's going on!” Cas sighed.

“I was tricked into creating a spell that would extract my grace and leave me human. Said grace was used to lock the doors of heaven and cause every Angel to fall. They all fell because of me.” He said quietly, and she could tell he was struggling to keep the tears at bay.

“Excuse me? What's going on?” Thea asked in confusion, voicing the others’ thoughts precisely.

“I'll explain as soon as I get this sorted.” Felicity snapped back with the venom she only used when someone insulted her computers or her hacking.

“It's not your fault Cas, forget that part for now, why aren't you with Sam and Dean? Cas,” She paused as if this question held more weight than even he could understand. “Cas, why aren't you with Dean?” He sighed, pure defeat in his actions, she sat him down in her seat, where he slumped, defeated.

“I'm not completely filled in on what happened, but Sam almost died, again, this time because of the trials. But when I finally got to them, Dean asked me to leave, the other Angels know by now it’s my fault and will be looking for me, I'm only putting them in danger.

But I do not think that's the only reason he asked me to leave. He’s certainly worried about Sam’s weakened state, but I believe he did his best to, what was the term?” He looks thoughtful before a bitter expression takes over “let me down easy. After all, I’m only human, and an extremely weak, useless one at that.” Felicity looked absolutely outraged.

“I'm sure there’s a different explain-” Cas suddenly became quite emotional.

“Don't you understand! He thinks I'm a weak little human! Just another thing he has to worry about! And now he’s finally rid of me!” Felicity looked at him hard.

“I'm going to get to the bottom of this, Cas.” With a few taps at the the screen there was a video chat request in progress. When no one picked up Felicity lost her patience. Her team didn't know what was going on, but Felicity was pissed, and when Felicity was pissed, entire governments tended to fall.

With a few more taps at her keyboard and she had full access to the live security footage of the bunker, a firewall her and Charlie had created easily bypassed. Then suddenly she held her earpiece up to her mouth, and her team immediately flinched, knowing with it that close even a whisper would sound like a shout.

“Dean Winchester get your dumbass outta bed and answer my damn call because you’ve got some explaining to do and you've better been possessed by a demon or Micheal himself to have a good enough reason for what you did.” Her voice was level and cold.

There was movement on the screen as a short haired guy fell off his bed, his comically large headphones tumbled off in the process. He scrambles to the desk to the right side of the room and suddenly the screen cuts to him looking at her through a camera, presumably on his laptop.

“Oh, hey Felicity, sorry for not calling earlier, been a bit busy. Oh!” He paused, his eyes landing on Castiel. “I'm glad Cas made it somewhere safe-” Felicity lost her last ounce of patience.

“No thanks to you! What the hell Dean! You don't contact me for almost two months! Letting me think you're either dead, or worse!” Felicity’s friends flinched, they knew worse meant torture, what kind of friends did Felicity have outside of them? And why are they just finding out about them?

“Then a freezing wet, hungry, human Cas ends up on my doorstep, making me think maybe he just needs a ride back to you guys, maybe he somehow ended up closer to Starling then Kansas, but it turns out he just came from Lebanon after you told him to leave! So you best start explaining yourself.” Her sentence ends abruptly and coldly, her expression could have killed.

“I-”  
“Hold that thought.” She suddenly disregarded him for Cas.

“You said you needed a warm shower?” Her tone was motherly, and Cas seemed less tense now.

“Y-yes.”

“Why don't you go take one now while I figure this out, you know how to take a hot shower, without burning yourself?” He nodded.

“I took several showers at homeless shelters along the way to Lebanon.” She smiled sympathetically at him. 

“Go take one, there will be fresh clothes waiting for you when you get out.” He nodded, Digg showed him the way. She knew Digg would get him some of Oliver's night clothes before rejoining the group.

“Continue. And the absolute truth, there's no one here who will judge you,” She gave the others in the room a pointed look that said more than words about how much she cared about this friend, though it was hidden from Dean by the way the computer light bounced off her glasses. “I might be mad, but I'll help find a solution first.” there was a long deep sigh before the guy, Dean, responded.

“We’ve been busy with the trials, trying to close the Gates of Hell forever. You know that Sam has been taking them on, since he did the first one while I was pushed out of the way.” She nodded, there was frustration in that fact for Dean.

“Well, he was getting sick after the second trial, and by the time he started the third he could hardly stand up straight he was so dizzy from being sick. Its was simultaneously ripping his insides apart and turning them to mush, slowly.” Everyone in the room shared glances of confusion and horror with each other, their looks of confusion weren’t even met with a glance.

“That last trial? It was going to kill him. The whole point was that there had to be a sacrifice, so he’d have to die and spend the rest of eternity in Hell with every demon on his ass for locking them in, who knows, it might have even rivaled his time in the cage with Lucifer.” Felicity gasped at the memory, while everyone else looked completely lost.

“So I went in and stopped him. I was so done with us sacrificing ourselves for the greater good, and hey, I'm selfish as fuck, and I stopped him. I explained that this would kill him, and in that moment I realized he’d known he was going to die this whole time, then he said, ‘so?’” Felicity sighed, tears appearing below her glasses.

“But I convinced him of how much I needed him, I promised him I'd get him better, that I'd save the day, that I'd finally be that hero that he used to think I was.” Dean’s voice broke, and the dam’s in the others’ eyes did too.

“Felicity I promised my baby brother on his deathbed that I'd make things better, and you know what? Not only was I unsure of how to fulfill that promise to begin with, as per usual I've made things so much worse.” His resolve cracked, as did their hearts, and tears marched down his face like little army men of emotion.

“What did you do?” Felicity finally asked, but it wasn't in the curious way a child would ask an adventurer what came next in his tail, it was more of a threat.

“Well first I took him to the hospital, they got him stable, but he was in a coma. He’d given up, accepted death. Then I prayed to Cas, told him I forgave him for whatever was happening with the angels, that it wasn't his fault. But somehow I had this feeling that they landed on deaf ears, not like he was ignoring me, but more like he wasn't there to hear them. I thought he was DEAD Felicity, thought I’d lost him forever, again. So I put out a distress call and told any angel who could get to me in the next day, they lost their ability to fly in the fall, to come and heal my brother, gave them my word as Dean Winchester that if they saved him I'd do whatever favor they may need, anything.” Felicity groaned.

“What have you gotten yourself into? Some kind of Angelic deal? Is that a thing?” Dean chuckled, but it was as bitter as it was strained.

“No, it's more of what I’ve gotten Sam into. And no, angels don't make deals like demons. He said he could heal Sam, but he was too weak to do it from the outside. He’d need to possess him to have enough energy for it.” Felicity’s brows furrowed in the way they did when she analyzed a situation.

“But you need to give consent. If Sam was in a coma how did he give consent, and something tells me he doesn’t know because you two are absolutely ridiculous!” Dean shrugged.

“My middle name’s Dean ‘fuck’s it up again’ Winchester, what can I say? But yeah, the consent thing. The Angel, Ezekiel, went in and made himself look like me in Sam’s head, then got him to say yes to, who knows what, and gives Sam complete mobility of his body, but he’s paranoid that the other angels are going to find out he’s hiding out in Lucifer’s vessel. That’s why I had to ask Cas to leave, you see, Sam can’t live, right now, without Zeke inside him. He threatened to leave if Cas didn’t.” Felicity’s jaw dropped and angry resolve went along with it.

“He made you choose between the two things you could never truly choose between, Sam, your younger brother, and Castiel, your best friend.” Dean nodded slightly. He couldn’t hardly breath through the softball sized lump in his throat.

“I’m sorry for yelling at your earlier, but Cas thinks you told him to leave because he’s useless to you. You need to explain things to him.” Dean nodded.

“That might help our friendship, but what am I supposed to do about Ezekiel? He’s begun threatening to leave if I try and tell Sam.” Felicity sighed.

“Cas is smart, he’s been around just a little after the start of time, I think he might know of something.” Dean nodded, smiling thankfully to her.

“I think it’s our turn for an explanation before Cas.” Dig responded before the moment could get any deeper. Felicity turned to him, a blush on her cheeks.


	2. Lemme Explain

**Summary for the Chapter:**

> Team Arrow finally gets an explanation

“I think it’s our turn for an explanation before Cas.” Digg responded before the moment could get deeper. Felicity turned to him, a blush on her cheeks.

“Yes, I guess that’s a little overdue?” Oliver gave her a ‘duh’ nod.

“Well… This is Dean Winchester, my pseudo brother, Cas’s friend. We met when I was pretty young, um, our parents were in the same business. After my mom died I traveled around with him, his brother, and their father for awhile, then I went off to college and got out of the life shortly after that.” Her team looked exasperated.

“Well thanks for telling us how you know this guy, now tell us about the supposed Angel in our bathroom and the brother who’s been possessed by Lucifer.” Digg asked. Felicity blushed heavier.

“Oh, right. Well… Monsters are real, every supernatural thing that goes bump in the night is real, Vampires, Werewolves, Witches, Ghosts, Wendigos, Shapeshifters…”

“Ghouls, Demons, Angels, Skinwalkers, Demi-gods, pagan gods, the whole shebang.” Dean continued for her. “Except aliens, most of the time it’s just fairies, don’t mess with those fuckers, you will get probed.” Dig stared at him, wide eyed in horror.

“But there are people out there, people whose whole job and purpose is to kill these things, hunt them. They save countless lives and a lot more people would go missing and die if it weren’t for them. Dean and his brother Sam are hunters, have been since their mother was killed by a demon when they were young. Their father became a hunter and taught them a lot of what they know. But they far outrank him now. They’re the greatest Hunters in the world. My mother was a hunter, that’s why my dad left. I started training to be a hunter when I was around 15, so not near as much experience as Sam and Dean.” They all took several steps away from the girl and the man behind the screen. Processing. Soaking it all in. Fitting these new pieces into the puzzle they had already started of Felicity Smoak.

“I wouldn’t say we’re the best-” Felicity cut him off.

“You’ve both died several times and been brought back by Angels, demons, and shear force of Will, you’ve battled archangels and won-” “-That was only Sam-” “-You’ve saved the entire world more than any other Hunter. Ever. You and I and Cas and Sam and Bobby and countless others know that.” The ‘and Ellen and Jo and Ash and many more…’ went unsaid.

“Anyway basically we’d met a few times when we were young and then when I’d finally started we kinda teamed up for awhile after my mom died. Their dad wasn’t happy but Sam had insisted. I went out on my own a little before Sam went to college, which inspired me to get out and go to college. Though our college experiences’ similarities end there. I got out, got my degree, and started working at QC, Sam on the other hand has some serious destiny and fate things tangled up with him, because one day their dad went missing, Dean arrives and asks Sam to help him on the case their dad had left behind, but when they got back to the college Sam’s girlfriend, Jess, was dead, the same way their mom died all those years ago…” She looked at Dean for permission, he nodded curtly, “Her stomach slit, stuck on the ceiling, burning.” Their eyes grew in horror and shock.

“I was four when it happened to my mom. I had to carry Sammy out of there. After that my dad became a revenge ridden alcoholic who raised us on the road. I had to raise my little brother. Then he- then he went to college, but because of me, he didn’t get to finish. But that was years ago. Long story short we’ve both died a lot and get brought back all the time and stuff, we’ve got a lot of ‘it’s your destiny’ hanging over our heads, and my friend who’s staying with you right now? He’s an Angel, or was, before his Grace, think of it’s as an Angel’s soul, was taken from him, which leaves a Human one. He’s not invinsible anymore, he’s gotta eat and sleep and pee like any normal person. I need you guys to look after him for me.” Dean gave them all stern looks that had them suddenly nodding along.

“Felicity, I am finished.” Cas said as he walked out of the shower area. He wore Oliver’s night clothes, which hung around his starving form.

“Dean has something to explain to you.” She immediately said, standing from her chair and patting it so he would sit.

“Y-Yes?” Cas asked nervously as he sat in the seat.

“Cas! I didn’t want you to leave for any of the reasons you think! It’s not ever the reason I told you!” The others tuned out their conversation as Dean explained to Castiel why he’d been an asshole.

“So he used to be an Angel?” Roy asked, looking unimpressed. Felicity rolled her eyes.

“Yes. That’s not normally what he looks like, he’s wearing street clothes instead of a suit and trench coat, that’s why I didn’t recognize him in the camera, besides, he’s suddenly had this need to eat, so he’s probably half starving and has no idea how to actually get food anywhere by a homeless shelter.” Roy looked guiltily at the floor.

“Before, when he was an Angel, he would have been possessing that body, the guy who it once belonged to is long dead, and Cas didn’t kill him by the way. His true form, the one that Angels normally take, is roughly the size of the empire state building.” They all looked impressed.

“So what exactly is wrong with Sam? Thea asked.

“He basically died, or his body did. Dean was desperate and had this angel possess him to heal him. Well now he’s taken up residence and won’t cooperate, if he leaves Sam now he’ll die from his injuries, and Sam has no idea.” Felicity answered.

“So Monsters? Heaven, Hell, they’re all real?” Oliver finally asked.

“Yes. Along with Purgatory,” Oliver’s jaw hardened, that was the English name of the island he had been marooned on. “But as you went to it’s island namesake, Dean went to the real purgatory, along with Cas, which is basically Monster Hell, all the Monsters Dean kills get sent to Purgatory after they die, where they’re to hunt and basically be feral for the rest of eternity.”

“What were those things you did to him when he first arrived, that flask he drank from and that cleaning solution on his hand?” Oliver asked after a moment of thought. Felicity nodded in understanding, it could be a bit confusing.

“Those were tests. He didn’t really look like he normally would, as I said before, and there are monsters that can make themselves look like anyone, so I had to make sure it was actually him. They wouldn’t affect a Human or an Angel. The flask was filled with Holy Water, which would burn him if he’d been possessed, the flask was made of silver, which would burn when he touched it if he was a shapeshifter, and the cleaning solution has Borax in it, which would melt the skin of a Leviathan.” Oliver tilted his head. She hadn’t mentioned that Monster before.

“What’s a Leviathan?” She visibly shivered at the thought of them.

“They’re a monster far older than Angels themselves. They’re far worse than Satan in my opinion, they’re hungry, evil creatures. They’re the reason Purgatory was created, it was created to contain them. Cas accidentally released them, it’s a long story and a sore spot for Cas, so don’t bring it up, but they started plans on conquering Earth for themselves. Y’know that super rich business guy that started taking over all those big companies a couple years ago, Dick Roman?” They all nodded, confused.

“He was the Leviathan leader, he was using a formula in corn syrup that caused human higher brain function to decrease, they were going to round us up and put us into farms for food.” Their eyes grew in horror.

“That’s why you started us on that training regimen that excluded anything manufactured, and when we started taking cheat days you told us Big Belly Burger was being sued for failing horribly at health inspections!” Diggle almost shouted, putting things together.

“That’s right, after Dean killed him, which is how he was accidentally transported to Purgatory, I used my awesome hacking skills to tear down his empire.” Thea smirked.

“Is that were that sudden flood of funds for the Glades came from?” Felicity blushed.

“It didn’t all go there, but yes. To sum up, lets pray to whoever’s listening up there anymore that we never have to encounter one, whereas you can force a Demon out of it’s body with enough Holy Water and salt, plus Sam and Dean have a knife that kills them, and Shapeshifters can be killed with silver, Leviathan can be hurt by borax, and they can be decapitated, but that will only slightly slow them down. Their bodies can reform as long as the head is within reach. There’s this special ritual that has to happen with a special bone of a nun and the blood of a Fallen Angel and stuff like that before you can actually permanently kill one.” They all silently prayed to whoever that they’d never have to see one.

“And what was that thing about being ‘Lucifer’s Vessel’?” Diggle asked.

“Vessel is what they call the people Angels possess, Cas’s name is Jimmy, though there are a few bloodlines Cas is able to possess safely, there is only one true bloodline and only a few people out of that bloodline that can truly be an Archangel’s vessel. Sam and Dean happen to be Lucifer and Michael’s true vessels.”

“But didn’t they say they your needed consent? Does that mean this Sam guy actually let Lucifer in?!” Thea asked incredulously.

“Well he had to,” Felicity clarified. “Lucifer had gotten out of the Cage, the thing created by God in Hell to keep him from destroying Humanity, and the only way to get him back in was for him to jump in himself. So Sam let him in, then overpowered him for control of his body and jumped in the Cage.” The rest of her team took a moment to register that.

“So he willingly flung himself into the pit to stop Satan?” Roy asked for clarification.

“Well… Yeah, Sam and Dean are always risking something to save the world. They have this hero/martyr complex. Kinda like you, Oliver.” He rolled his eyes, though she was right, he’d never tried to throw himself into Hell.

“That’s nuts. How have we never known about this? Why didn’t you tell us, anyways, Felicity?” Thea asked the question they’d all tried to refrain from. The blond shrugged.

“It’s kinda a big thing to know, y’know, we had all this stuff going on and I didn’t think it was all that important. We focus on Starling City because it’s our terf, there isn’t much Supernatural things that go on here, there’s enough evil humans here anyway. Besides, it’s not like we could have done anything about what was happening, we’re only human and non of us have enough monster fighting experience to actually help. I’ve only taken down a small Vamp nest, a few ghosts, and a ghoul in my time, not exactly a good track record. Also…” She trailed off, not looking any of them in the eye. “I knew you’d want to help, or do something, and it’s even more dangerous than what you do now, and I didn’t want you to suddenly have a pack of Demons on your ass. What you do allows you to continue to be Oliver Queen along with the Arrow. What Sam and Dean do? It allows them to be seen as mass murderers that the FBI have thought dead at least twice. There’s no room for two seperate lives with what they do, you’re either all in or all out, or dead.” Oliver came forward, placing a steady hand on her shoulder.

“It’s ok Felicity, you were trying to protect us, but next time, when we say no secrets, we literally mean no secrets, we’re gonna tell everyone everything, even if it puts them in danger. And that includes all of us.” As he made eye contact with his team everyone gave their nod of agreement.


End file.
